Same plant, same boat as you. I live on Long Island and we too have 30-40 ppm Nitrates in the water. Been using NilocG dry ferts, GH booster, CSM+B and Fe added. I have my plants now 3 weeks and many leaves are gone. The outer tips on some of them are yellow/brown. All are emersed with very little submersed (Cuban) leaf. Mine came from PlantedAquaquarium Central. I was wondering if a 5% Clorox dip might have did them in. I have a Fluval Planted 3.0 (16" to substrate). pH with CO2 is 6.4, GH 6, KH 2. CO2 on DC is light green/green. I am still dialing it in. Only added pressurized CO2 a week ago. Plants were in the tank for 2 weeks without. 76 deg F. Only difference is that I have been adding the full NO3 for the EI dosing. Following the concentrations for EI listed at NilocG website. Weekly water changes of 10 gal in a 29 gal tank. My Temple plant is finally reddening up and growing leaves. No height thought. Foxtail hasa doubled in height. S repens has nearly carpeted the section I wanted to do. Bacopa Carolina is to be used more like a small bush is growing great. Crypt undulata and Wendtii red are starting to throw off more leaves. Buce and anubia petite are also doing fine. Even the algae growing on my wood is pearling (7" from light). I am only concerned with my Mermaid weed and temple plants and I think the temple, with all the roots it has shot out all over the place and the fact the leaves are starting to grow might be out of the woods. All of my plants were purchased at the same time in a new tank from that supplier. Really was impressed with how they shipped and packed. Really great and would use them again.
I am hoping your issues might be mine as well.
All the best.